It is hardly possible to generalize all telegram channels and speak unambiguously. Theoretically, the legitimate seller may well be on telegram.
But it's still a possibility. that the scammer will be much higher in the telegram. There are a lot more scammers out there, if only because it's much easier. Absolutely anyone can create a channel at any time. You can create as many new channels as you like every day.
It is still more difficult to create a website on the darknet. It's even harder to earn a reputation. The fraudster will have to constantly change links or create clones, and each new link requires new clients to be attracted.
Therefore, you should treat telegram sellers even more carefully.